1. Field of the Invention
The present invention relates to a rendering technology and, more particularly, to a rendering technology for generating image adapted for a display device.
2. Description of the Related Art
With improvement in the technology for fabricating a thin display such as a liquid crystal display and a plasma display, and the reduction in prices, an extensive variety of display devices are currently available around us. Display devices display high-quality images played back by a DVD player or moving images generated by computer graphics.
In order to display image data output from a computer or a DVD player on a display device, a display controller is necessary which converts an image signal into a format compatible with the specification of a display device, by converting the horizontal frequency or the vertical frequency of an image signal.
In order to output an image to a display of the NTSC/PAL/SECAM television system, the image should be output to adapt to the vertical synchronous frequency of the NTSC/PAL/SECAM system. This requires conversion of the resolution and frame rate of an image rendered by a graphics processor.
The specification (e.g., frame rate and resolution) of an image signal that can be displayed varies from device to device. For conversion of an image signal by a display controller in adaptation to the specification of destination display devices, various converters are necessary. Disadvantageously, this results in an increase in circuit scale and fabrication cost. Configuring a converter by hardware for shipping results in limited flexibility and expandability because it will be impossible to address new display technologies and standards efficiently.
Further, a timing difference between a vertical synchronizing signal concurrent with the rendering of an image by the graphics processor and a vertical synchronizing signal concurrent with the display of the image on a display device may exercise unpredicted influence on the frame rate conversion of the image, making it difficult to maintain the quality of the image displayed on the display device.